As is well known to those versed in the art of door edge switches, and the like, a high degree of versatility and adaptability is required to enable a switch construction to be employed in many different environs, for example as a safety door edge in sensing the presence of an obstacle to door movement, as a safety machinery stop switch to prevent machinery operation with persons in dangerous positions, as in signalling switches for use in public vehicles, door treadles and the like. The lack of versatility and diversity in prior switch constructions has limited usage and increased costs by requiring many different custom made products. Examples of prior art which are known to applicant include U.S. Pat. Nos. 4,051,336; 3,986,577 and 3,118,984.